A fuel cell has been proposed as a clean, efficient and environmentally responsible power source for electric vehicles and various other applications. In particular, the fuel cell has been identified as a potential alternative for the traditional internal-combustion engine used in modern automobiles.
One type of fuel cell is the polymer electrolyte membrane (PEM) fuel cell. The PEM fuel cell includes three basic components: a cathode; an anode; and an electrolyte membrane. The cathode and anode are generally formed from a finely divided catalyst, such as comminuted platinum. The electrolyte membrane is sandwiched between the cathode and the anode to form a membrane-electrode-assembly (MEA). The MEA is typically disposed between porous diffusion media (DM), such as carbon fiber paper, which facilitates a delivery of reactants such as hydrogen to the anode and oxygen to the cathode. The hydrogen is catalytically disassociated in the anode to generate free protons and electrons. The electrons from the anode cannot pass through the electrolyte membrane, and are instead directed through an electric load to perform work before being sent to the cathode. The protons pass through the electrolyte to the cathode. The protons react with the oxygen and the electrons in the cathode to generate water. Individual fuel cells can be stacked together in series to form a fuel cell stack. The fuel cell stack is capable of supplying a quantity of electricity sufficient to power a vehicle.
Contamination of the electrolyte membrane after prolonged periods of use is known to affect the performance and durability of the PEM fuel cell. Typical contaminants may include pollutants from air drawn from the atmosphere as well as internal sources. Contaminants and errant chemical species may leach or migrate from fuel cell components, such as adhesives, seals, and the like, that can gradually break down over the lifetime of the fuel cell.
It has been difficult to sufficiently assess PEM fuel cell contamination. In particular, the determination of contaminant type and quantity has been made difficult by the presence of the platinum catalyst in the MEA interfering with traditional analytical techniques. Additionally, although it is known to use air filters in fuel cell systems to scrub the cathode air supply, conventional air filters do not sufficiently remove the contaminants which may negatively affect the PEM fuel cell stack performance and the useful lifetime of the PEM fuel cell stack.
There is a continuing need for a device that sufficiently filters contaminants and errant species from the reactant streams of the fuel cell stack. Desirably, the device facilitates an analysis of the types and quantities of contaminants and errant species present at the electrolyte membrane of the fuel cell stack.